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* [PATCH v2] cpuidle: sysfs: Use sysfs_emit/sysfs_emit_at instead of sprintf/scnprintf
@ 2025-09-15 17:41 vivekyadav1207731111
  0 siblings, 0 replies; 3+ messages in thread
From: vivekyadav1207731111 @ 2025-09-15 17:41 UTC (permalink / raw)
  To: rafael, daniel.lezcano; +Cc: linux-pm, linux-kernel, Vivek Yadav, Joe Perches

From: Vivek Yadav <vivekyadav1207731111@gmail.com>

The ->show() callbacks in sysfs should use sysfs_emit() or
sysfs_emit_at() when formatting values for user space. These helpers
are the recommended way to ensure correct buffer handling and
consistency across the kernel.

See Documentation/filesystems/sysfs.rst for details.

No functional change intended.

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: vivek yadav <vivekyadav1207731111@gmail.com>
---
Changes in v2:
- Do not modify the variable 'i'; leave it unchanged.
---
 drivers/cpuidle/sysfs.c | 34 +++++++++++++++++-----------------
 1 file changed, 17 insertions(+), 17 deletions(-)

diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c
index d6f5da61cb7d..61de64817604 100644
--- a/drivers/cpuidle/sysfs.c
+++ b/drivers/cpuidle/sysfs.c
@@ -27,14 +27,14 @@ static ssize_t show_available_governors(struct device *dev,
 
 	mutex_lock(&cpuidle_lock);
 	list_for_each_entry(tmp, &cpuidle_governors, governor_list) {
-		if (i >= (ssize_t) (PAGE_SIZE - (CPUIDLE_NAME_LEN + 2)))
+		if (i >= (ssize_t)(PAGE_SIZE - (CPUIDLE_NAME_LEN + 2)))
 			goto out;
 
-		i += scnprintf(&buf[i], CPUIDLE_NAME_LEN + 1, "%s ", tmp->name);
+		i += sysfs_emit_at(buf, i, "%.*s ", CPUIDLE_NAME_LEN, tmp->name);
 	}
 
 out:
-	i+= sprintf(&buf[i], "\n");
+	i += sysfs_emit_at(buf, i, "\n");
 	mutex_unlock(&cpuidle_lock);
 	return i;
 }
@@ -49,9 +49,9 @@ static ssize_t show_current_driver(struct device *dev,
 	spin_lock(&cpuidle_driver_lock);
 	drv = cpuidle_get_driver();
 	if (drv)
-		ret = sprintf(buf, "%s\n", drv->name);
+		ret = sysfs_emit(buf, "%s\n", drv->name);
 	else
-		ret = sprintf(buf, "none\n");
+		ret = sysfs_emit(buf, "none\n");
 	spin_unlock(&cpuidle_driver_lock);
 
 	return ret;
@@ -65,9 +65,9 @@ static ssize_t show_current_governor(struct device *dev,
 
 	mutex_lock(&cpuidle_lock);
 	if (cpuidle_curr_governor)
-		ret = sprintf(buf, "%s\n", cpuidle_curr_governor->name);
+		ret = sysfs_emit(buf, "%s\n", cpuidle_curr_governor->name);
 	else
-		ret = sprintf(buf, "none\n");
+		ret = sysfs_emit(buf, "none\n");
 	mutex_unlock(&cpuidle_lock);
 
 	return ret;
@@ -230,7 +230,7 @@ static struct cpuidle_state_attr attr_##_name = __ATTR(_name, 0644, show, store)
 static ssize_t show_state_##_name(struct cpuidle_state *state, \
 			 struct cpuidle_state_usage *state_usage, char *buf) \
 { \
-	return sprintf(buf, "%u\n", state->_name);\
+	return sysfs_emit(buf, "%u\n", state->_name);\
 }
 
 #define define_show_state_ull_function(_name) \
@@ -238,7 +238,7 @@ static ssize_t show_state_##_name(struct cpuidle_state *state, \
 				  struct cpuidle_state_usage *state_usage, \
 				  char *buf)				\
 { \
-	return sprintf(buf, "%llu\n", state_usage->_name);\
+	return sysfs_emit(buf, "%llu\n", state_usage->_name);\
 }
 
 #define define_show_state_str_function(_name) \
@@ -247,8 +247,8 @@ static ssize_t show_state_##_name(struct cpuidle_state *state, \
 				  char *buf)				\
 { \
 	if (state->_name[0] == '\0')\
-		return sprintf(buf, "<null>\n");\
-	return sprintf(buf, "%s\n", state->_name);\
+		return sysfs_emit(buf, "<null>\n");\
+	return sysfs_emit(buf, "%s\n", state->_name);\
 }
 
 #define define_show_state_time_function(_name) \
@@ -256,7 +256,7 @@ static ssize_t show_state_##_name(struct cpuidle_state *state, \
 				  struct cpuidle_state_usage *state_usage, \
 				  char *buf) \
 { \
-	return sprintf(buf, "%llu\n", ktime_to_us(state->_name##_ns)); \
+	return sysfs_emit(buf, "%llu\n", ktime_to_us(state->_name##_ns)); \
 }
 
 define_show_state_time_function(exit_latency)
@@ -273,14 +273,14 @@ static ssize_t show_state_time(struct cpuidle_state *state,
 			       struct cpuidle_state_usage *state_usage,
 			       char *buf)
 {
-	return sprintf(buf, "%llu\n", ktime_to_us(state_usage->time_ns));
+	return sysfs_emit(buf, "%llu\n", ktime_to_us(state_usage->time_ns));
 }
 
 static ssize_t show_state_disable(struct cpuidle_state *state,
 				  struct cpuidle_state_usage *state_usage,
 				  char *buf)
 {
-	return sprintf(buf, "%llu\n",
+	return sysfs_emit(buf, "%llu\n",
 		       state_usage->disable & CPUIDLE_STATE_DISABLED_BY_USER);
 }
 
@@ -310,7 +310,7 @@ static ssize_t show_state_default_status(struct cpuidle_state *state,
 					  struct cpuidle_state_usage *state_usage,
 					  char *buf)
 {
-	return sprintf(buf, "%s\n",
+	return sysfs_emit(buf, "%s\n",
 		       state->flags & CPUIDLE_FLAG_OFF ? "disabled" : "enabled");
 }
 
@@ -358,7 +358,7 @@ static ssize_t show_state_s2idle_##_name(struct cpuidle_state *state, \
 					 struct cpuidle_state_usage *state_usage, \
 					 char *buf)				\
 { \
-	return sprintf(buf, "%llu\n", state_usage->s2idle_##_name);\
+	return sysfs_emit(buf, "%llu\n", state_usage->s2idle_##_name);\
 }
 
 define_show_state_s2idle_ull_function(usage);
@@ -550,7 +550,7 @@ static ssize_t show_driver_name(struct cpuidle_driver *drv, char *buf)
 	ssize_t ret;
 
 	spin_lock(&cpuidle_driver_lock);
-	ret = sprintf(buf, "%s\n", drv ? drv->name : "none");
+	ret = sysfs_emit(buf, "%s\n", drv ? drv->name : "none");
 	spin_unlock(&cpuidle_driver_lock);
 
 	return ret;
-- 
2.25.1


^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH] cpuidle: sysfs: Use sysfs_emit/sysfs_emit_at instead of sprintf/scnprintf
@ 2025-09-15 14:31 Rafael J. Wysocki
  2025-09-19 16:56 ` [PATCH v2] " vivekyadav1207731111
  0 siblings, 1 reply; 3+ messages in thread
From: Rafael J. Wysocki @ 2025-09-15 14:31 UTC (permalink / raw)
  To: vivek yadav
  Cc: Joe Perches, Rafael J. Wysocki, daniel.lezcano, linux-kernel, linux-pm

On Sun, Sep 14, 2025 at 5:20 PM vivek yadav
<vivekyadav1207731111@gmail.com> wrote:
>
> Hi @Rafael J. Wysocki ,
>
> Is there any update for me on this patch ?

As I said before, please do not rename the variable.

Thanks!

^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2025-09-20 11:07 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2025-09-15 17:41 [PATCH v2] cpuidle: sysfs: Use sysfs_emit/sysfs_emit_at instead of sprintf/scnprintf vivekyadav1207731111
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2025-09-15 14:31 [PATCH] " Rafael J. Wysocki
2025-09-19 16:56 ` [PATCH v2] " vivekyadav1207731111
2025-09-20 11:07   ` Rafael J. Wysocki

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